Lens systems used in typical cameras can be divided into three categories as glass lens systems, plastic lens systems and hybrid lens systems. In recent years, cameras have begun to be incorporated in portable terminals such as mobile phones and laptop computers. When being applied in portable terminals, lens systems need to satisfy the oft-conflicting requirements of low cost, lightweight, and excellent optical performance, for example, high-resolution. However, glass lens systems are difficult to satisfy the low cost and lightweight requirements. Plastic lens systems can satisfy the low cost and lightweight requirements, but the plastic lens systems are prone to be affected by outside environment, scratch resistance and temperature endurance of outside lenses of the plastic lens systems are relatively low.
In typical hybrid lens systems, glass lenses and plastic lenses are aligned differently. One typical hybrid lens system includes, from an object side to an image side, a biconvex first lens with positive refracting power, a biconcave second lens with negative refracting power, and a biconvex third lens with positive refracting power. The first lens and the second lens are made from plastic material, and both have aspheric surfaces. The third lens is made from glass material. Therefore, the hybrid lens system can reduce cost and correct aberrations in a certain extent. However, the first lens as the outside lens is made from plastic materials, scratch resistance and temperature endurance thereof are relatively low. Another typical hybrid lens system is provided. The hybrid lens system is consisted of a first lens, a second lens, and a third lens. The first lens and the second lens are spherical lenses made from glass material. The third lens is made from plastic material and has aspheric surfaces on both surfaces. However, the hybrid lens system is difficult to satisfy a high-resolution requirement.
What is needed, therefore, a hybrid lens system which has high scratch resistance and excellent optical performance is desired.